Lung cancer is caused by disordered proliferation of tracheal, bronchial, or alveolar cells as a result of loss of their normal functions. The number of people who have died of lung cancer is the largest of the total of cancer deaths, accounting for 17% of the total death, and about 1.3 million people worldwide die of lung cancer per year.
Treatments for lung cancer are roughly divided into surgical operation (surgical therapy), anticancer agents (chemotherapy) and radioactive irradiation (radiation therapy), but the effectiveness of treatment will vary depending on the tissue type of lung cancer. For example, although a definite diagnosis of lung cancer is made by a pathologist based on his cytohistopathological diagnosis on a microscope specimen, small cell lung cancer, which constitutes about 20% of lung cancer cases, has often reached an advanced stage at the time of discovery because it generally has a high grade of malignancy and will rapidly grow and spread and will often metastasize to other organs. For this reason, chemotherapy or radiation therapy is often used for treatment of this cancer, but the prognosis is poor because small cell lung cancer will often recur although it is relatively sensitive to these therapies. On the other hand, in the case of non-small cell lung cancer, which constitutes the remainder of about 80%, surgical therapy is considered for use until a certain stage, but there is little opportunity to use surgical operation in the subsequent stages where chemotherapy or radiation therapy is mainly used for treatment. Therefore, chemotherapy is an important choice for treatment of any type of lung cancer.
EGFR (Epidermal Growth Factor Receptor) is a receptor type tyrosine kinase recognizing epidermal growth factor (EGF) as a ligand, and plays an important role in differentiation, development, proliferation, and survival of cells in normal tissues. It has hitherto been reported that EGFR is overexpressed in various malignant tumors (Journal of Cellular Physiology Vol. 194, No. 1, p. 13, 2003), and causes acceleration of cell proliferation and division of cancer cells, metastasis, or the like (Endocrine-Related Cancer, Vol. 8, No. 1, p. 11, 2001). Further, it is thought that the overexpression of EGFR is a factor resulting in poor prognosis (Journal of Clinical Oncology, Vol. 21, No. 20, p. 3798, 2003).
It is known that in some patients with non-small cell lung cancer (NSCLC), cancer cells have mutation for constitutive activation of the kinase activity of EGFR, such as mutation of leucine to arginine at the position 858 (L858R mutation) and deletion mutation of the exon 19 of EGFR, and gefitinib and erlotinib, which are inhibitors of the tyrosine kinase activity of EGFR, exhibit high effectiveness (Proc. Natl. Acad. Sci. USA Vol. 101, No. 36, p. 13306, 2004; and Science Vol. 304, p. 1497, 2004). However, resistance to these inhibitors is shown in many patients after treatment. It is known that secondary mutation in EGFR occurs in about half of these patients with resistance and threonine is replaced with methionine at the position 790 (T790M mutation), and a recombinant enzyme of EGFR having T790M mutation introduced thereinto or cells of H1975 or the like which endogenously have T790M mutation exhibit substantial resistance to gefitinib and erlotinib (Cancer Res. Vol. 67, No. 13, p. 6253, 2007, Oncogene Vol. 28, p. S24, 2009). In addition, it has been reported that an irreversible inhibitor of an EGFR T790M mutation kinase inhibits the proliferation of cell lines expressing EGFR T790M mutation, and regresses the tumor volume in an EGFR resistant mutation (T790M/L858R) model mouse (Non-Patent Document 1).
It has been reported that a compound represented by the following formula (A) has an irreversible inhibitory activity on an EGFR T790M mutation kinase (Patent Document 1 and Non-Patent Document 1), and the inhibitory activity on an EGFR T790M mutation kinase of a pyrimidine compound disclosed as Compound 2-2 (WZ4002) has been disclosed.

(For the symbols in the formulae, refer to the corresponding publications)
It has been reported that the pyrimidine compounds represented by the following formula (B) (Patent Documents 2 and 4), the formula (C) (Patent Documents 3 and 5), and the formula (D) (Patent Documents 3 and 5) have an inhibitory activity on various kinases containing EGFR, and an EGFR T790M mutation kinase, and it is also described that the pyrimidine compounds are useful for treatment of cancer.

(For the symbols in the formulae, refer to each of the publications)
It has been reported that a compound having a pyrazine ring represented by the following formula (E) has an inhibitory activity on JAK and Trk among the tyrosine kinases, and is useful for treatment of myeloproliferative diseases or cancer (Patent Document 6).

(wherein Ring A represents a 5- to 6-membered heteroaryl ring which may be substituted with one or more R1's, R1 represents C1-6 alkyl or the like, Ring B represents a carbocycle or heterocycle which may be substituted with one or more R6's, R6 represents C1-6 alkyl, —N(R6a)C(O)R6b, or the like, R6a represents H, C1-6 alkyl, or the like, R6b represents C1-6 alkyl, C2-6 alkenyl, or the like, R2 represents —C(O)N(R2a)2 or the like, R2a represents H, C1-6 alkyl, or the like, R3 represents C1-6 alkyl or the like, X represents —O— or the like, and R5 represents C1-6 alkyl or the like. For the other symbols in the formulae, refer to the corresponding publication.)
However, there is no disclosure of an action on an EGFR T790M mutation or an EGFR kinase in the Document above, and further, the pyrazinecarboxamide compound represented by the formula (I) as described later according to the present invention has a different structure from that of the compound of the formula (E) in L2.
It has been reported that a compound represented by the following formula (F) has an inhibitory activity on an EGFR and a mutation EGFR kinase including T790M mutation, and an inhibitory activity on an EGFR T790M mutation kinase of a pyrimidine compound disclosed as Compound XIII-1 has been described (Patent Document 7).

(wherein X1 represents —O—, —NH—, or the like, B represents pyridine-2,4-diyl, pyrimidine-2,4-diyl, or the like, and m represents 0 or 1. For the other symbols, refer to the corresponding publication.)
It has been reported that a compound represented by the following formula (G) inhibits the activity of a Her-2 kinase and an EGFR kinase (Patent Documents 8 and 9). Further, it has been reported that a compound represented as HKI-272 of the following formula (also called neratinib) has a proliferation inhibitory activity on EGFR T790M mutation cell lines (Non-Patent Document 2).

(For the symbols in the formulae, refer to the corresponding publications).
Furthermore, it has been reported that a compound represented by the following formula (H) has an inhibitory activity on an EGFR and a mutation EGFR kinase including T790M mutation (Patent Document 10). Further, an inhibitory activity on EGFR and mutation EGFR kinases of a compound represented as BIBW2992 (also called afatinib) and an action on a cancer-bearing mouse with EGFR T790M mutation expressing cells have been reported (Non-Patent Documents 3 and 4).

(For the symbols in the formulae, refer to the corresponding publications).
It has been reported that a compound represented by the following formula (J) has an inhibitory activity on an EGFR and a mutation EGFR kinase including T790M mutation (Patent Document 11). Further, it has been reported that a compound disclosed as PF-00299804 of the following formula (also called dacomitinib) has an inhibitory activity on an EGFR and mutation EGFR kinase and an action in a cancer-bearing mouse with EGFR T790M mutation expressing cells (Non-Patent Documents 5 and 6).

(For the symbols in the formulae, refer to the corresponding publications).
It has been reported that a pyrazinecarboxamide compound included in the following formula (K) has an inhibitory activity on ALK, RET, ROS, and FLT3 among the tyrosine kinases, and is useful for treatment of various cancers (Patent Document 12).

(wherein X represents a group of the formula (K-1) or the formula (K-2). For the other symbols, refer to the corresponding publication.)
However, there is no disclosure of an action on EGFR T790M mutation or EGFR kinase in the above-described documents, and further, the pyrazinecarboxamide compound represented by the following formula (I) according to the present invention has a different structure from that of the compound of the formula (K) in that a substituted vinyl group is bonded to -L2-Y-L3-M.
It has been reported that a quinazoline compound represented by the following formula (L) has an inhibitory activity on an EGFR and a mutation EGFR kinase including T790M mutation (Patent Document 13).

(wherein A represents acyl substituted with alkyne or alkene. For the details, refer to the corresponding publication.)